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5.4.
How to replace a faulty UPS in a
parallel system
Press over the key in any UPS for more than 3 seconds to
shutdown all the inverters. The acoustic alarm will beep for 3
seconds. The equipments that belong to the current parallel
system will transfer to "bypass mode".
Put all the equipments on manual bypass. To do it remove
the cover from manual bypass switch, which is located at the
back of each equipment and turn all the switches to position
"byPASS".
Keep in mind that on "bypass mode" or with the
switch on position "byPASS", the loads will be ex-
posed to fluctuations of voltage, frequency and mains faults
or blackouts, so in case it is possible choose one day with the
lowest probability of faults (days without fluctuations, days
without storms,... ) and do it as fast as possible.
Turn "off" the input, output and bypass circuit breaker pro-
tections (this last one when it is available) from the protection
panel and corresponding to the equipment to replace.
Disconnect the communication bus and all power connec-
tions, and remove it. in equipments installed as rack, remove
the screws that fix it to the cabinet previously.
Put the manual bypass switch of the new UPS, to position
"byPASS". To do it remove the protection cover of the manual
bypass located in the rear side and act over itself.
Put the new equipment that replaces the faulty one and re-
connect it. Follow the instructions stated in section 4.3.9.2, to
connect them in parallel.
For equipments installed as rack, put the screws that fix it to
the cabinet previously.
• Turn "on" the input and bypass circuit breakers (this last one, if
it is available) from protection panel, and corresponding to the
new UPS.
UPSs supply output voltage from bypass. Check the lCD from
control panel in case there were any warning or error information.
Measure the output voltage of the new UPS, check the voltage
difference is below 1 V. in case the difference were higher than 1
V, double check the wiring and associated instructions.
• Put back the cover of the manual bypass of each UPS.
• Press over the start up key for more than 3 sec. in any of the
UPSs and all of them will start up. All UPSs will transfer to "normal
mode”.
Measure the output voltage in the power blocks of the parallel
system and the output terminals of the new UPS, to check the
voltage difference is under 0,5 V. in case the difference were
higher than 1 V, the UPSs have to be set (contact the KESS Sup-
port-Team).
• Press over the shutdown key in any UPS for more than 3 sec-
onds and each one will be shutdown, supplying output voltage
through the bypass.
Turn “on” the output circuit breaker switch of the distribution
panel, corresponding to the new integrated equipment. The
complete parallel system will supply output voltage, through the
bypass.
• Remove the cover of the manual bypass in each UPS.
• Transfer the equipments with the manual bypass ("byPASS" po-
sition) to position "UPS". Do it in the switches of all equipments.
• Put back the protection cover of the manual bypass switch of all
equipments, also check the torque of the fixing screws, otherwise
any of the limit contacts of this cover could be activated and the
manual bypass too.
• Press over the start up key for more than 3 sec. in any of the
UPSs and all of them will start up, finally the parallel system will
be working on "normal mode”.
load/s are running and protected by the parallel system again.
5.5. Manual bypass Switch (maintenance)
5.5.1.
operating principle
integrated manual bypass in all UPS from KESSUPS 91RT from 4 to
10kVA is available, but a wrong use can cause irreversible conse-
quences for both the UPS and connected loads at its output. There-
fore, it is important to respect the manoeuvring of the switch as it is
stated in the following sections.
5.5.2. Transference to maintenance bypass
• The procedure to transfer from normal mode to maintenance by-
pass is the same for a single equipment or a parallel system, less
the quantity of actions:
For a single equipment.
– Press over the key of the UPS for more than 3 seconds
to shutdown the inverter. The acoustic alarm will beep for
3 seconds. The equipment will transfer to "bypass mode".
For a parallel system.
– Press over the key in any UPS for more than 3 seconds
to shutdown all the inverters. The acoustic alarm will
beep for 3 seconds. The equipments that belong to the
current parallel system will transfer to "bypass mode".
Put all the equipment/s on manual bypass. To do it remove
the cover from manual bypass switch, which is located at the
back of each equipment and turn all the switch to position
"byPASS.
in parallel systems, proceed in the same way in each equip-
ment.
Keep in mind that on "bypass mode" or with the switch
on "byPASS" position, the loads will be exposed to fluc-
tuations of voltage, frequency and mains faults or blackouts, so
in case it is possible, choose one day with the lowest probability
of faults (days without fluctuations, days without storms,... ) and
do it as fast as possible.
The UPS still supplies output voltage, from mains directly or
through the static bypass line (in those installations that it is
available), through the manual bypass of the equipment.
Also, if the protection panel has manual bypass switch, re-
move the mechanical lock and turn the switch "on" (byPASS).
in this case and in this case only, turn the output switch/es
from distribution panel to "off", depending if there is only
